It is important, for saving time and costs but also for safety, to be able to sense the presence of a piping, and in particular a fluid flow piping, and to locate it accurately, without digging into the ground, nor destroying structures, during subsequent works.
Several methods can be used to carry out the sensing of buried piping.
The electromagnetic sensing is the most used method. This electromagnetic sensing may be performed using an electromagnetic sensor comprising in a known manner a transmitter, such as a current generator, and a receiver. In this case, the electromagnetic sensing is carried out on the one hand by injecting, using the transmitter of the electromagnetic sensor, an electrical signal, which produces an electromagnetic field, into an electrically conductive sensing member associated to the piping to be identified and disposed along the path of said piping, through connection housings installed along the piping in order to serve as injection points of the electrical signal, and on the other hand, by capturing using the receiver of the electromagnetic sensor, the electromagnetic field created by the alternating current circulating in the sensing member.
In a manner known per se, the sensing member is covered by a cylindrical sheath made of an electrically insulating material and is fastened on the piping to be identified using fastening means, such as for example, circlips, self-gripping strips, or adhesive strips.
Such fastening means enable, mostly, a displacement of the sensing member on the outer surface of the piping to be identified, and this in particular when the piping is of circular section. These movements of the sensing member may lead to an inaccurate positioning of the sensing member, and therefore to an inaccurate and difficult sensing of the associated piping.
However, taking into account the drastic evolution of the accuracy standards in terms of sensing of buried piping, it is necessary to ensure an optimum positioning of the sensing member, including after burial of the associated piping.